The demand of a solid state imaging device (image sensor) as a semiconductor device used in electronic equipment has been increasing. For the solid state imaging device, a structure of a so-called back-illumination has been proposed in which a drive circuit is formed on the surface of a semiconductor substrate and a back surface is a light receiving side, in order to intend to improve photoelectric conversion efficiency and sensitivity with respect to incident light. In the backside illumination type solid state imaging device, it is possible to increase a light receiving aperture ratio of the light receiving surface, and to increase an incident area of light in the same chip area.
Further, in the backside illumination type solid state imaging device, wiring and contact pads may be provided below a sensor, as compared to a front side illumination type. Therefore, the backside illumination type solid state imaging device has a structure in which the wirings are provided on the surface of a substrate, and thus the miniaturization of a device is possible, as compared to the front side illumination type solid state imaging device having the same light receiving area. Then, the device is miniaturized, such that it is possible to increase a chip yield in a wafer surface.
Meanwhile, in the backside illumination type solid state imaging device, since there are no contact pads on the upper surface, a method of connecting the contact pads from the outside is a problem. As a solution method, a method has been proposed in which an external connection terminal is provided in an outer peripheral portion of a circuit forming region of the semiconductor device in which various active elements and circuits are arranged (for example, see PTL 1). The external connection terminal is configured to be able to be connected from the surface on the light receiving surface side of the backside illumination type solid state imaging device.